How to Use Kling 4.0: Sound, References, Edits and Prices

Kling 4.0 is Kuaishou's newest video model. One model covers text to video, first and last frames, reference pictures and videos, and editing a clip you already have, all with generated sound. It makes 3 to 30 seconds at 720p or 1080p.

We ran four real jobs with it on November 14, 2026. Below is each prompt, what came back, what it cost and how long it took, followed by the prices and the prompt habits that worked.

Text to video, with sound and a spoken line

Sound is not an option you turn on: Kling 4.0 always makes it, and the prompt decides what it is. We asked for a scene with music, ambience and one spoken line:

Golden hour on a seaside boardwalk, handheld 35mm, shallow depth of field. An old man in a flat cap plays a waltz on an accordion; a small scruffy dog sits beside his open case. A woman drops a coin in the case; he nods to her and says: "Merci, madame." Sounds: the accordion waltz, waves on the shore, gulls, the coin clinking. Photorealistic, warm natural color. No text, no logos.

He says "Merci, madame" word for word, the accordion plays a waltz, and the waves and gulls are there. Kling 4.0 also cut on its own to a close-up of the dog and the coin, then back to him, the way an editor would. If you want one continuous shot instead, say so in the prompt.

Kling 4.0 or Kling 4.0 Flash

Kling 4.0 Flash is the faster, cheaper Kling 4.0: 720p only, 3 to 20 seconds, at 123 credits a second instead of 207. We gave it the same prompt:

Kling 4.0, 1,035 credits

Kling 4.0 Flash, 615 credits

Flash kept one wide shot and showed the whole action: the woman walks in, drops the coin, he looks up. Kling 4.0 framed it tighter and cut to an insert, which feels more like a film. Both spoke the line word for word. Flash is the one to iterate with; Kling 4.0 is the one for the final take, and the only one with 1080p and a last frame.

Put a product in the shot

Reference pictures are how you keep something exact: a product, a character, a place or a style. You name each picture in the prompt by position, as @image_1, @image_2 and so on. We made a mug with Seedream 5.5 and asked Kling 4.0 to put it in a café:

Close-up in a sunny café, handheld: a smiling barista in a denim apron slides @image_1, filled with a latte with a leaf pattern, across a white marble counter toward the camera, then lets go. Keep the mug exactly as in @image_1: sage green with a white hand-painted wave pattern. Sounds: the espresso machine hissing, the mug sliding on marble, soft café chatter. Photorealistic. No text, no logos.

The mug kept its color, its handle and the white waves all the way through, and the latte art came out as asked. You can send up to 10 pictures in all, counting a first and last frame, at no extra charge.

Edit a clip you already have

Send a clip and describe the change. The result keeps the clip's length, shape and movement. We sent Kling 4.0 its own boardwalk clip:

Turn @video_1 into a snowy winter evening: snow falling, the boardwalk and railing white with fresh snow, warm string lights along the railing, the old man in a wool coat and scarf. Keep his accordion music, the dog, the coin and every movement and cut the same.

The clip we sent

Edited by Kling 4.0

Same shots, same cut to the dog, same coin, same "Merci, madame", now in snow under string lights. It did change him, though: the flat cap is gone, so list the person among what stays when it matters. An edit is billed differently from a new clip: the input and output seconds are both counted, at a lower rate. Kling's 5-second clips run 5.04 seconds, so ours rounded up to 6 seconds each way: 12 billed seconds at 124 credits, 1,488 credits.

What Kling 4.0 costs

Per second of video, on any paid plan:

• With a video input (a clip to edit, or reference videos), the rate drops to 124 credits a second at 720p, 186 at 1080p and 82 on Flash, but you pay for the output seconds plus the longer of the input and the output.
• Reference pictures and frames cost nothing extra.
• A job that fails costs nothing, and the price shows before you start.
• Plans: Kling 4.0 and Flash need a paid plan, from $10 a month for 11,000 credits; see pricing.

Prompt habits that worked

• Write the sound into the prompt. List the music, the ambience and the effects, and put dialogue in quotes in a sentence of its own: he says: "Merci, madame." Both models spoke it word for word.
• Expect cuts, or ask for none. Kling 4.0 may cut between shots inside one clip. That is great for a scene; for a product loop or a single camera move, ask for one continuous shot.
• Name pictures by position and say what must not change. "Keep the mug exactly as in @image_1: sage green with a white hand-painted wave pattern" held the product exactly.
• For an edit, list what stays. "Keep his accordion music, the dog, the coin and every movement and cut the same" kept all of those; what we didn't list, like his cap, could change.
• Draft on Flash, finish on Kling 4.0. Flash costs 40% less, and on the same prompt it finished in about half the time; move to Kling 4.0 when you need 1080p, a last frame or the extra polish.

How to use Kling 4.0 on BudgetPixel

1. Open the Video Workshop and pick Kling 4.0 or Kling 4.0 Flash.
2. Write the prompt, sound included.
3. Add pictures or a video if you want them: a first frame (and a last frame on Kling 4.0), reference pictures, or a clip to edit.
4. Choose the length and resolution. The price shows before you start.
5. Generate. Our clips took 2 to 4.5 minutes.

From code, the same model is on the BudgetPixel API:

curl -X POST https://api.budgetpixel.com/v1/videos/kling-4.0 \
  -H "Authorization: Bearer $BUDGETPIXEL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "Close-up in a sunny café: a barista slides @image_1 across a marble counter toward the camera. Sounds: espresso machine, soft chatter.",
    "reference_images": ["https://your-site.com/mug.jpg"],
    "length_seconds": 5,
    "resolution": "720p"
  }'
# then poll GET /v1/videos/{id} until status is succeeded; the clip is at video_url

The other inputs are image (first frame), end_image (last frame), reference_videos and video (a clip to edit); aspect_ratio takes 16:9, 9:16, 1:1 or 21:9 when no frame or clip sets the shape. For Flash, use /v1/videos/kling-v4-flash. AI assistants connected to BudgetPixel's MCP server reach both through generate_video.

Kling 4.0 or Seedance 2.5?

Both make video with sound and both take references. In our earlier test, where both got the same four prompts, Seedance 2.5 followed camera directions more closely, and Kling 4.0 cost less and leaned toward spectacle. The full side-by-side: Kling 4.0 vs Seedance 2.5.

Sources: our own Kling 4.0 and Kling 4.0 Flash jobs on November 14, 2026; prices and limits from BudgetPixel's model catalog, checked the same day.